In recent years, portable players such as WALKMAN (Registered Trademark of Sony Corporation) which allow a user to enjoy music and so forth readily in a hand-free fashion have been spread widely. Also a portable player has been proposed which is configured so as to be more convenient in carrying by adopting wireless connection between the body and a pair of headphones of the portable player (for example, Japanese Patent Laid-Open No. Hei 7-143587).
A wireless portable player is a reproduction apparatus which makes use of a radio communication system to transmit and receive music data between the body and the headphones. Where music data are transmitted and received by a radio communication system, for example, music data are transmitted from the body by radio communication and received and reproduced by the headphones. Music can be enjoyed with the body placed in a bag or the like and with the headphones secured to the head, and the user is not disturbed by a cable, which is convenient to the user.
However, in a case wherein a different user who has a similar wireless portable player is in the proximity of the user, music data transmitted from the body may be received by the headphones of the different user. If the different user receiving the data records the data illegally and then distributes the data to another different user, then this gives rise to a problem in regard to the copyright.
Incidentally, digital contents such as music contents recently suffer from increasing illegal distribution and exchange of contents without a license of the copyright together with popularization of the Internet and increase in speed of operation and capacity of a PC (Personal Computer) and so forth. Therefore, in order to prevent such illegal acts as just described, a copyright management system which applies restrictions to distribution and utilization of contents is being spread.
Where the copyright management system is used, such a situation that data transmitted from the body of a wireless portable player are received and reproduced by the headphones of another wireless portable player as described above can be prevented.
However, there is a problem that, as a result of restriction to distribution and utilization of contents, an essential pleasure of music that the music is shared with many and unspecific persons is limited. Also there is another problem that a content provider is less likely to spread the music widely.